function like(btn, entityType, entityId){
    $.post(
        CONTEXT_PATH + "/like",
        {"entityType":entityType,"entityId":entityId},
        function (data) {
            data = $.parseJSON(data);
            if(data.code == 0){
                // 往两个子标签里写入内容
                $(btn).children("i").text(data.likeCount);
                $(btn).children("b").text(data.likeStatus==1?'已赞':'赞');
            }else{
                alert(data.msg);
            }
        }
    );
}